Modern vehicles, in particular electric vehicles, are driven by electric motor arrangements which each have an electric machine for driving the vehicle and power electronics for providing phase currents for the electric machine. Due to the physical properties of the electric machine and of the power electronics, power losses in the form of waste heat occur during operation of such electric motor arrangements, said power losses leading to an increase in temperature of the electric motor arrangement. A high intrinsic temperature of the electric motor arrangement can lead to a power loss of the electric machine and in extreme cases even to failure of the power electronics. In order to prevent this, the waste heat has to be discharged before damage arises.
For this purpose, double-sided cooling systems have been proposed in which, however, mounting stiffness of a rotor is reduced by the introduction of ventilation openings. A further problem results from the fact that high-temperature air drawn in cannot cool a bearing outer ring, and so the rotor bearings become prematurely worn due to temperature.